Nerve Injuries Flashcards
Describe the X-ray below
This is an adequate x-ray of the left arm, both the joint above and below the fracture can be seen.
There is a fracture of the mid shaft of the humerus
It is a simple, complete spiral fracture, there is some varus angulation (of the distal fragment). We cannot assess for dorsal/volar angulation as we need another view.
It doesn’t appear shortened but looks rotated.
Following a mid-humeral shaft fracture, a patient presents with numbness across dorsal 3.5 digits and difficulty extending finger and wrist
a) What do you suspect has been injured during the fracture?
b) Why is this commonly injured?
c) How else might you injure this structure, atraumatically?
a) radial nerve injury (wrist drop)
b) commonly injured at it runs in the spiral grove on the posterior humerus
c) compression or the radial nerve, ‘Saturday night palsy’ due falling asleep in an awkward position compressing the nerve
Read the case study below
a) What is your main diagnosis?
b) List one differential diagnosis?
c) What test is required to confirm diagnosis?
a) Carpal Tunnel Syndrome
b) Cervical radiculopathy (C6/7) or injury of the medial nerve at the elbow
c) diagnosis sually clinical (tinnels and phalens), nerve conduction studies to confirm (ↆ onduction through median n,)
List 4 RFs for carpal tunnel syndrome
- Rheumatoid Arthritis (this case)
- Pregnancy
- Hypothyroidism
- Occupational – hand arm vibration syndrome (HAVS)
- Diabetes
- Trauma
- Acromegally
- Obesity
How would you manage a patient with carpal tunnel syndrome?
(conservative, medical, surgical and MDT)
a) What can you see on the x-ray below?
b) Which nerve is at risk of injury?
c) What clinical signs might you expect to find if there is injury to the nerve?
a) Anterior shoulder dislocation – humerus completely out of glenoid fossa (posterior less common - lightbulb sign)
b) Axillary nerve
c) loss of sensation at the regimental badge, difficulty/inability to abduct shoulder due to loss of deltoid (once relocated)
Read the case study below
a) What is your main diagnosis?
b) List one differential diagnosis?
c) List 4 findings on examination for the above ddx
a) Injury or compression of the ulna nerve ie. cubital tunnel syndrome
b) Cervical radiculopathy (C8 dermatome), diabetic neuropathy, MS
c) Findings:
- ↆ sensation in little finger and the ulnar border of ring finger
- wasting of interosseous muscles
- weakness of finger abduction and adduction.
- Froment’s test
a) Which muscles does the ulnar nerve supply, and what are the actions of those muscles?
b) What is the sensory distribution of the ulnar nerve?
Sensation to ulnar 1.5 digits dorsal and palmar
How would you manage a patient with cubital tunnel syndrome?
(conservative and surgical)
Conservative:
- Splinting to prevent excessive flexing at night.
- Physiotherapy
Surgical:
- Surgical decompression of ulna nerve in cubital tunnel
A man presents with foot drop, he cannot dorsiflex his foot and is walking with a high stepping gait
a) Which nerve is most likely damaged?
b) Why is this nerve usually injured?
c) List 2 ways in which this nerve is commonly injured
a) Common peroneal nerve - foot drop
b) Passes very superficially round the head of the fibula before branching into the superficial and deep peroneal nerves
c) Commonly injured by:
- external compression e.g direct pressure, or a cast,
- trauma – eg. fractured head of fibula, blunt injury, iatrogenic during surgery
Read the case study below
a) What red flag features will you ask her about?
b) What are your differentials?
c) How would you manage this lady?
a) Red flags
- loss of bowel/bladder control
- weight loss
- fever
- sadle anaesthesia
b) Sciatica, Symphysis pubis dysfunction| (loosening of ligaments)
c) Management
- Physiotherapy
- Heat packs and support belts
- Simple analgesia
What analgesia must avoid during pregnancy and why?
Ibuprofen and NSAIDS - can cause premature closure of the ductus arteriosus
Label the Ascending Pathways
a) What do dorsal columns transmit?
b) Where do they Decussate?
c) What are the two tracts within and how do they differ?
a) Fine touch proprioception and vibration
b) Medulla in the medial lemniscus
c) Cuneate (T6 and above) and Gracile (T6 and below)
a) What do the spinothalamic tracts trasmit?
b) Where do they Decussate?
a) Anterior - crude touch and pressure, Lateral - pain and temperature
b) Decussates in the anterior horn of the spinal column (substantia gelatiosa)
Label the Descending Pathways
Read the case study below
a) What is the eponymous name of this syndrome?
b) What symptoms will he likely have? (sensory and motor)
a) Brown Sequard Syndrome (rare)
b) Sensory
- ↆ fine touch, pressure, vibration & proprioception on the left
- loss of pain, temperature & crude touch on the right
Motor
- Ipsilateral paralysis (hemi-plegia)
- Spasticity
- Brisk reflexes
State the functional defect and associated tract in Brown Sequard Syndrome for abnormalities:
- Below the level of the lesion
- At the level of the lesion
- Above the level of the lesion
